"Taste" - what is it, definition of the term
Gustatory perception is a chemical sensory system that evaluates soluble compounds through specialized receptors located on the oral epithelium. When molecules dissolve in saliva, they bind to taste‑receptor cells within taste buds, triggering neural signals that travel via cranial nerves to the brain’s gustatory cortex. This pathway enables discrimination of fundamental qualities—sweet, salty, sour, bitter, and umami—and contributes to the assessment of nutritional value, toxicity, and overall palatability of foods and beverages.
Detailed information
Gustatory perception in arthropods such as ticks, true bugs, lice and fleas relies on specialized chemosensory structures located on the mouthparts and body surface. These structures convert chemical stimuli from potential hosts or the environment into neural signals that guide feeding behavior and habitat selection.
Sensory apparatuses include:
- Labial and maxillary palps equipped with taste sensilla that detect soluble compounds.
- Tarsal and leg sensilla that sample surface chemicals during locomotion.
- Antennal gustatory receptors in many true bugs, providing additional detection capacity.
- Ventral plate receptors in lice and fleas that assess host skin secretions.
The primary functions of these chemosensory systems are:
- Identification of suitable hosts by recognizing specific amino acids, sugars and fatty acids.
- Determination of optimal attachment sites based on pH and ionic composition.
- Avoidance of toxic or deterrent substances present on the skin or in the environment.
Ticks possess a pair of ventral hypostomal sensilla that respond to carbon dioxide and host odorants, while also expressing gustatory receptors for blood‑borne metabolites. True bugs, such as bed bugs, use stylet‑borne sensilla to evaluate blood chemistry before penetration. Lice exhibit mouthpart‑associated taste pits that sense keratin‑derived peptides, and fleas rely on foreleg sensilla to detect host body heat combined with chemical cues.
Disruption of these chemosensory pathways offers a target for control strategies. Synthetic compounds that block receptor activity can reduce host‑finding efficiency, and repellents that mask attractive chemicals interfere with feeding initiation. Understanding the molecular basis of gustatory perception across these groups supports the development of species‑specific interventions.